Rotary pivoted hammer



May 27, 1930. o. J. WILLIAMS ROTARY PIVOTED HAMMER Filed Jan 25, 1928 Patented May 27, 1930 UNITED STATES OLIVER J'. WILLIAMS, IBURLINGAME, CALIFORNIA ROTARY PIVOTED HAMMER Application filed January 25, 1928.

This invention relates to certain new and useful improvements in rotary pivoted hammers, for shredding or similar grinding machines for reducing alfalfa or other material,

the peculiarities of which will be hereinafter fully described and claimed.

The main object of my invention is to produce increased efficiency of the hammers in shredding and reducing the feed material,

both in the operation and the life of the hammers.

The hammers commonly used have a single operative edge across the front face of the hammer head, and sometimes another at the back that becomes operative when the hammer is reversed after wearing downthe front face edge. There is only a comparatively small sharp edge that does the actual cutting. This gets dull very easily, and then the resulting product, such as the meal when shredding alfalfa, gets stringy and full of hairs makmg an irregular shaped meal product, with reduced output capacity.

My improved hammer presents multiple teeth on the front face at different radial distances from the pivot axis, and also on the outer end that is close to the arcuate cage that co-operates in the shredding action. Teeth are also provided on the back to; allow reversal. Furthermore, the length of each cutting edge is substantially doublechor otherwise increased, by widening laterally the head end of the hammer, which also increases proportionately the weight of this end and lengthens the radius of the center of percussion from the pivot axis. Other advantages will appear in the descriptionof the'exemplification of my, invention hereinafter set forth.

In the accompanying drawing on which like reference numerals indicate corresponding parts, Fig. 1 represents a verticalsectional view across the shaft of a: rotary shredder, or similar machine, showing one form of my improved shredding hammer; Fig. 2, a vertical section of the casing on the line 22 of Fig. 1 showing a side'view of the cylinder therein Fig. 3, a side and edge View of a toothed hammer of uniform thickness;

CAD

Fig. 4, a similar view of a toothed hammer Serial No. 249,284.

vith a triangular thickened head; Fig. 5, a similar view of a toothed hammer with a rectangular thickened head; Fig. 6, a similar view of a toothed hammer with widened split head; and Fig. 7 a side, front and plan view of a toothed hammer with angular widened head. v v

The numeral 1 designates a rotary shaft, mounted in suitable bearings 3, with pulley t or other means for rotating it. ()n the shaft are mounted a series of spaced discs 5 through which, eccentric to the shaft, pass a set of hammer rods 6, on which are pivotally mounted rotary beater hammers by means of eyes at the inner ends of the shanks 7 located in. the spaces between the discs. The hammer heads on the outer ends of the shanks beyond the periphery of the discs, cooperate with an arcuate cage 8, preferably perforated metal, supported in a suitable casing 9 enclosing the cylinder and having a feed hopper 1O forentra-nce of the feed material. Initial reduction is effected on a grinding plate 11, or other means, and further reduction is accomplished by the hammers in cooperation with the screen cage till the product is fine enough to pass the openings therein.

The outer head end of the shank has its a front face provlded with multiple teeth 12, at

different radial distances and cylindrical planes of rotation from the pivoteye. These teeth are of any suitable shape, preferably formed by notches, the outershorter faces of the teeth'and the inner longer faces forming practically intersecting planes that are respectively transverse and inclined to the length of the hammer, so as to form teeth that point upward andoutward, as indicated in detail Figs. 3-7 inclusive. The back or rear of the hammer is similarly notched to form teeth 13 in pairs front and back lying in concentric cylindrical planes to allow of reversing the hammer on its rod when the front teeth become worn.

These teeth on front and back are shown in pairs opposite each other, and each tooth is preferably formed byv a pair of substantially intersecting planes, one of which: is transverse to the aXis and the other is inclined inward to said axis.

The extreme outer end face of the hammer is also notched to form teeth 14 extending radially so their tips are closely adjacent to the screen cage, and the faces of the teeth are inclined to the direction of rotation, to force the material being reduced through the screen openings. These notches forming teeth are provided on the front, the back and the extreme outer end face, in combination or-otherwise. V

The shank and toothed head are the same thickness in the hammer shown in Fig. 3. When such a hammer is used, there is a space left between adjacent heads substantially equal to the thickness of the discs, indicated by t 1e dash lines. Generally however, I prefer to widen the head so that its sides are 7 more or less closely acent to the hammer beyond the sides radial distances from the'pivot.

heads on both sides and nearly fill the space corresponding to the intervening disc, as 1ndica'ted by dash lines in Fig; 4. In this ure the head is triangular with outward flaring front and back, and is projecting in the plane of rotation.

In 5, the toothed head is practically rectangular with projecting frontand back and isllaterally thickened.

v In 6 the front and back project as in Fig. 5, while the end has a deep notch lengti wise that bifurcates the head, the two forks are bent sidewise to widen the head and each fork is toothed on the front and back. The front and plan views show the effect of the laterally bent forks and the teeth thereon.

In Fig. 7 the head is diamond shaped in plan forming a sharp vertical or radial toothed edge at front and back in pairs in concentric cylindrical planes successively as before 7 stated, but with the sides of the teeth also inclined towards each other by the angular form of head showmand the extreme end also notched transiersely to form teeth. The side edges of the diamond head extend of the shank and overhang the discs so as nearly to close the space between adjacent shanks, as indicated by dash lines. I 7

in these forms, Fig. 1 7 inclusive, the front and back faces of the head extend beyond the shank in the plane of rotation, and have transverse notches forming teeth'at dill-aren't Also the triangular head of Fig. 4, the rectangular CUT heads of Figs. 5 and 6, and the diamond head all are wider or thicker laterally discs of the cyiinder.

The outer teeth on the front and rear ed es have a longer radial face than the adjacent inner teeth so thatas the wear proceeds, these teeth will still retain a cutting edge till than the shank tooverhang the interposed outer operative pos tion. Especially in Fig. the outward progection of the front and rear in the plane'of rotation, brings the raued wear brings the next inner tooth to dially disposed teeth into substantially ra dial planes through the eye of the hammer, so that as each tooth becomes the outer tooth by process of wear, it acts on the material in a similar manner as the outer teeth did when the hammer was full length.

The teeth on a row of such widened toothed hammers form practically continuous parallel horizontal lines of cutting edges and afford a combined action, while allowing a flexible wavy oscillation in operation due to the independent pivotal mounting of the hammers and the variable resistance of the material. Oscillation of the hammers upon the rod on which they are pivoted, causes w er in the eye and on the rod. The oscillation and consequent wear are reduced by the increased weight of the thickened head, since the heavier head locates the centerof percussion further away from the-pivot, thereby increasing the radius to said center of percussion and to the center of gravity, and also its tendency to maintain a straight-out radial position under centrifugal influence.

To illustrate,According to'wellknown engineering formulas, it is determined that the center of gravity of the hammer Fig. 3 is located at a point 15, and the center of percussion at a point 16. Tn'the rectangular thickened head Fig. 5, the center of gravity is located at a point 17, and the center of percussion at a point 18,-each having moved outward from the pivot axis dueto'the thickened head. of Fig.5. The centerof percussion is the point at which, if a resisting force is apof rotation. Thus the. blow of the hammer head in reducing material, reacts on the hammer rod much" less in Fig. 5 hammer than in Fig. 3 hammer, which is'of greatpractical value in operation. In Fig. 5 the center of percussion is located well out in the head; in Fig. 3, it is not.

Also the greater Weight of the thickened head increases the centrifugal force of Fig. 5 hammer compared with Fig. 8-hammer, so that the former has lesstendency to oscillate in operation and hence there is less wear on the eye and rod.

The wear of the end of the head is'greater at the outer front tooth and diminishes toward the back, as indicated by the curved dash line 19. Whenso worn, the hammer should be reversed, and further wear is indicated by the dash line20 showing the outer back corner worn down nearly to the side notch. If the hammer then have its pivotal length increased by suitable means, its efficiency will be largely restored. Such means I have shown as consisting of an elongated insert piece 21 having aneye nearer one .end and inserted inan cated nearer the bottom end of the shank and thus further from the head (or vice versa) as indicated in Fig. 4. Such an insert piece may be used with any of the hammers shown, or others.

I claim:

1. The combination with rotary spaced discs and a hammer rod mounted therein, of a pivoted hammer having a relatively nonturning insert piece adjustably fixed in the hammer shank at its inner end so as to form one piece therewith and oscillate in unison, and a head end having teeth radially disposed,said piece having an eye for said rod radially movable in the shank to vary the operative length, substantially as shown and described.

2. A rotary pivoted hammer having teeth and having an elongated opening near. the inner end of its shank, and an elongated insert piece relatively non-turning reversibly mounted in said opening and thus fixed in the shank at each insertion so as to oscillate in unison therewith,said piece having an eye nearer one end than the other and thus adapt-- ed to vary the distance from said eye to the head in each inserted position.

3. A rotary pivoted hammer having an an gular head with front and rear faces projecting beyond its shank and having teeth, and arelatively non-turning insert piece with an eccentric eye mounted near the inner end of the shank,said piece being relatively fixed to the shank at each insertion so as to oscillate in one piece therewith and set said teeth nearer to or further from said eye, substantially as described and for the purpose set forth.

t. A rotary pivoted hammer having an eye for pivotal mounting and an angular head provided with multiple notches radially disposed on its front and rear edges,said notches forming teeth at different radial dis tances from the eye and the outer teeth having a longer radial face to the adjacent notch than the inner teeth thereby presenting the sharp outer edge till the wear brings the next adjacent teeth into effective outer position, substantially as described. 7

5. A rotary pivoted hammer having an eye for pivotal mounting and a head thicker than the shank and having its front and rear edges projecting outward in the plane of rotation so as to lie in substantially radial planes through the eye, and provided with multiple notches forming teeth radially disposed at different radial distances from the eye,the extreme outer teeth having a longer radial face to the adjacent notch than the inner, substantially as described.

In testimony whereof I have aflixed my signature.

* OLIVER J. WILLIAMS. 

